Transient Multiphase Flow and Mechanistic Gas Hydrate Modeling of an Anti-Agglomerant Field Trial in the Norwegian Continental Shelf

Gas hydrate formation in multiphase flow systems poses significant operational risks in offshore oil and gas production. Anti-agglomerants (AAs), a class of low-dosage hydrate inhibitors (LDHIs), have emerged as effective chemical additives that decrease interparticle cohesive forces and hydrate–wall adhesion, thereby preventing hydrate particles from agglomerating, sticking to the pipe wall, and allowing their transportation as a dispersed slurry. To the best of the authors’ knowledge, and based on a comprehensive literature survey performed, this study represents the first application of an anti-agglomerant in the Norwegian Continental Shelf. The design of the operational procedure and the analysis of the field trial outcomes were guided by a transient mechanistic gas hydrate model fully coupled to a one-dimensional transient multiphase flow simulator, which incorporates hydrate growth kinetics, deposition, and sloughing phenomena. The field trial procedure consisted of a batch injection of a mixture of AA and brine, followed by a 32 h shut-in period, allowing the fluids to cool and reach hydrate formation conditions, and then a successful production restart. Analysis of simulation results and field data support the conclusion that the anti-agglomerant contributed to preventing plugging.